Linear Coefficient Research Articles

Effect of Nd2O3 concentration on radiations shielding properties of Gd3+-doped borate glasses: a theoretical investigation using Phy-X Software

In this study, we investigate the shielding properties of borate glass systems [30Li2O + 10MgO + 5Gd2O3 + (55-x)B2O3 + xNd2O3], where x = 0, 0.1, 0.5, 1.0, 1.5 and 2.0 mol %: by varying x, the concentration of both B2O3 and Nd2O3 changes. We exploit robust Phy-X software, developed for photon shielding and dosimetry, to carry out the calculations for the determination of the shielding properties such as linear and mass attenuation coefficients, effective atomic number, half value layer, mean free path, and tenth value layer versus photon energy in the range of 0.08 to 15 MeV. The HVL decreases from 9.91 to 8.86 cm while moving from sample 1 to sample 6, which is attributed to its highest density among all samples. Compared to the other five samples, the results indicate that sample 6 with 2.0 mol % Nd2O3 is more likely to attenuate gamma and X-ray photons due to its lower tenth values of tenth value layer, half value layer, mean free path, and higher mass attenuation coefficient and effective atomic number. In the energy range of 0.08–15 MeV, the mass attenuation coefficient for sample 1 varies between 86.96 and 0.024 cm2/g, while the mass attenuation coefficient for sample 6 with the highest Nd concentration ranges between 104.66 and 0.026 cm2/g. We find that among all samples, sample 6 with 2.0 mol % Nd2O3 is more likely to attenuate the gamma and X-ray photons, i.e. the incorporation of Nd2O3 improves shielding properties, as indicated by the increase in linear and mass attenuation coefficients and effective atom number with increasing the Nd2O3 concentrations, while the half value layer, mean free path, and tenth value layer decrease with increasing Nd2O3 content. Therefore, the glass with composition 30Li2O + 10MgO + 5Gd2O3 + 53B2O3 + 2Nd2O3 turns out to be the most promising material among the studied glass samples for the X-ray and gamma-ray shielding.

4D Dynamic contrast-enhanced breast CT: Phantom-based reconstruction parameter optimization for iodine quantification.

Four-dimensional dynamic contrast-enhanced breast CT (4D DCE-bCT) offers promising high-resolution spatial and temporal imaging capabilities for the characterization and monitoring of breast tumors. However, the optimal combination of parameters for iodine quantification in image space remains to bedetermined. This study aims to optimize a dedicated bCT system to perform long dynamic contrast-enhanced scans with high spatio-temporal resolution while maintaining a reasonable radiation dose. Our protocol includes the acquisition of a high-quality prior image that is reconstructed with a polychromatic iterative algorithm (IMPACT). The acquisition of the post-contrast sequence is continuous but sparse and these images are reconstructed using prior image constrained compressed sensing (PICCS). A four-step optimization process is performed using images of a physical phantom. First, the optimal tube current is selected by taking the noise level into account. Second, the optimal number of angles is selected based on the absence of streak artifacts. Third, the number of iterations in IMPACT is specified at the lowest value that achieves the highest spatial resolution. Finally, the number of iterations in PICCS is determined based on the quantitative accuracy of a range of iodine concentrations. When a high-quality prior image is available, the imaging of post-contrast images can be performed using just 40 projection angles with a tube current of 32 mA. The noise level in the post-contrast images is inherited from the prior image and no streak artifacts are visible. Mean difference between the linear attenuation coefficients of samples containing iodine reconstructed with IMPACT using all 360 projections and PICCS using 40 projections is 0.0004 at most. The spatial resolution of images reconstructed with PICCS is lower than the one of IMPACT images and is concentration dependent. The cut-off frequency at 10% modulation transfer function drops from 1.55 in the prior image to 0.9 when the target with the largest concentration is evaluated. The total mean glandular dose of the protocol does not exceed 22.5mGy. This study found the optimal acquisition and reconstruction parameters for a low-dose dynamic contrast-enhanced bCT protocol. The numerical accuracy of the proposed protocol was ensured by performing a physical phantomstudy.

Study of attenuation characteristics for novel neonatal head phantom in diagnostic radiology using Monte Carlo simulations and experiments.

This study presents the design and validation of a neonatal head phantom using innovative heterogeneous composite materials customized to replicate the X-ray attenuation properties of neonatal cranial structures. Analysis of Hounsfield Unit (HU) data from 338 neonatal head CT scans informed the design of epoxy resin-based composites with additives such as sodium bicarbonate, fumed silica, and acetone to simulate bone, brain matter, cerebrospinal fluid (CSF) and hyperdense abnormalities. The cranial bone substitute (60% epoxy resin, 40% sodium bicarbonate) achieved a density of 1.60 g/cm³, with HU values (574.67-608.04) closely matching clinical ranges. Brain matter (95% epoxy resin, 5% acetone) achieved HU values (35.27-43.61), aligning with clinical means, while the CSF-equivalent material (80% epoxy resin, 15% fumed silica, 5% acetone) matched neonatal CSF HU values (14.53-17.02). A mass substitute for hyperdense abnormalities exhibited HU values (56.16-61.07), enabling differentiation from normal brain. Validation included Monte Carlo simulations and experimental CT imaging, showing close agreement in linear attenuation coefficients, with deviations below 11% across energy levels. Mass attenuation coefficients from simulations and XCOM software were consistent, with deviations under 0.7%, confirming the materials dosimetric reliability. The phantom, with a cylindrical geometry (9 cm diameter, 10 cm length), provides accurate attenuation properties across 80-120 kVp energy levels, with deviations below 5% between experimental CT numbers and simulation data. This phantom offers a robust platform for neonatal imaging research, enabling impactful dose optimization and imaging protocol adjustment and supports improved diagnostic accuracy in pediatric imaging.

Pengaruh Live Shopping Shop Tokopedia @Npureofficial Terhadap Keputusan Pembelian Produk Skincare

This research aims to determine the influence of Shop Tokopedia live shopping on purchasing decisions for N'Pure Skincare. The theory used is AIDA (Attention, Interest, Desire, Action) by Elias St. Elmo Lewis. The research method use is a quantitative method with data collection in the form of a questionnaire distributed to followers of the TikTok account @npureofficial with a sample size of 100 respondents. The sampling technique uses non-probability sampling with a purposive sampling method. The data analysis methods used include normality test, simple linear regression test, partial test (t), and coefficient of determination test (R2). The data was tested using IBM SPPS Statistics 30 software. The research results show that Shop Tokopedia live shopping has a significant influence on purchasing decisions for N'Pure skincare products by 61.9% and the remaining 38.1% is influenced by other factors.

Mutual Information-based Feature Selection Strategy for Speech Emotion Recognition using Machine Learning Algorithms Combined with the Voting Rules Method

This study proposes a new approach to Speech Emotion Recognition (SER) that combines a Mutual Information (MI)-based feature selection strategy with simple machine learning classifiers such as K-Nearest Neighbor (KNN), Gaussian Mixture Model (GMM), and Support Vector Machine (SVM), along with a voting rule method. The main contributions of this approach are twofold. First, it significantly reduces the complexity of the SER system by addressing the curse of dimensionality by integrating a focused feature selection process, resulting in considerable savings in both computational time and memory usage. Second, it enhances classification accuracy by using selected features, demonstrating their effectiveness in improving the overall performance of the SER system. Experiments carried out on the EMODB dataset, using various feature descriptors, including Mel-frequency Cepstral Coefficients (MFCC), Perceptual Linear Prediction (PLP), and Linear Prediction Cepstral Coefficients (LPCC), showed that the best performance was achieved by GMM, with an accuracy of 85.27% using 39 MFCC features, compared to an accuracy of 82.55% using a high-dimensional vector with 111 features. Furthermore, applying the Joint Mutual Information (JMI) selection technique to extracted MFCC features reduces the vector size by 23.07% while improving the accuracy to 86.82%. These results highlight the effectiveness of combining the feature selection process with machine learning algorithms and the voting rules method for the SER task.

The Influence of Individual Characteristics and Non-Physical Work Environment on Employee Performance

This study aims to determine the effect of individual characteristics and non-physical work environment on the performance of employees at the Praya Tengah Sub-District Office. The population in this study consists of all employees at the Praya Tengah Sub-District Office, with the sampling technique using purposive sampling. This type of research is associative quantitative research. Data processing in this study used SPSS 26.0, where validity tests, reliability tests, classical assumption tests, multiple linear regression analysis, significance tests (t-test), and determination coefficient tests (R Square) were conducted. The results of this study show that the non-physical work environment has a greater influence on employee performance at the Praya Tengah Sub-District Office. Based on the t-test results, it was found that t count > t table (1.993 > 1.697) or the significance value (0.026 < 0.05), indicating that the non-physical work environment has a positive and significant effect on the performance of employees at the Praya Tengah Sub-District Office.

Muscle Mass Index Decline as a Predictor of Lung Function Reduction in the General Population.

This study explores the link between muscle mass decline and lung function deterioration, which can worsen respiratory health by reducing exercise capacity and quality of life. The relationship between muscle mass index (MMI) changes and lung function in the general population remains unclear, especially as muscle mass fluctuates with aging. We aimed to clarify this dynamic relationship by examining how changes in muscle mass impact pulmonary function and the development of respiratory symptoms. We utilized the Ansan and Ansung Cohort Study of the Korean Genome and Epidemiology Study (KoGES) database, a large-scale prospective cohort, enrolling participants aged 40 to 69 years with lung function and body composition measurements. Over 12 years, data were collected biannually. The study assessed associations between changes in MMI and lung function trends, with cT1-T3 calculated using the linear regression coefficient and stratified by tertile. Survival analysis was then performed to examine differences in time to first airflow obstruction (AFO) and exacerbation among the tertiles. A total of 2956 participants were enrolled in this study. At baseline, participants with higher MMI tended to be younger, had fewer co-morbidities and exhibited better lung function. Those with a steeper MMI decline rate exhibited a more rapid forced expiratory volume in 1 s (FEV1) decline over a 12-year follow-up (cT1: 43.3 mL/year, cT2: 38.4 mL/year, cT3: 33.2 mL/year, p < 0.001). Forced vital capacity (FVC) decline were more pronounced in groups with greater MMI decline rates (cT1: 38.5 mL/year, cT2: 32.8 mL/year, cT3: 26.0 mL/year, p < 0.001). Although, the time to first AFO did not differ significantly among T1-T3 groups, the time to first exacerbation related to wheezing event was significantly lower in cT3 group than in cT1 group (HR: 0.786, 95% CI: 0.629, 0.982). A faster decline in MMI was associated with more rapid decline of both FEV1 and FVC and a higher risk of developing exacerbations of respiratory symptom. Although AFO was not associated with changes in MMI, further research is needed to explore the long-term relationships between muscle mass and the effects of preventive interventions aimed at maintaining muscle mass and respiratory health.

Development and validation of a RP-HPLC method for simultaneous determination of cimetidine, metoprolol tartrate and phenol red for intestinal perfusion studies.

A new reversed phase high-performance liquid chromatography (RP-HPLC) method, with a short analysis time and easy to apply, was developed for the simultaneous detection of cimetidine (CIM), metoprolol tartrate (MT) and phenol red (PR) for use in intestinal perfusion studies. The analysis was performed with phosphate buffer (pH 5.0, 12.5mM)-acetonitrile mixture as mobile phase and C18 column (Inertsil ODS-3; 5µm, 4.6×250 mm) as stationary phase. Gradient analysis conditions were used and the acetonitrile ratio in the mobile phase varied from 10 to 50% in 10min. Total run time for analysis was 10min and the injection volume was 20µL. Detection of compounds was performed at 207nm. Under optimum HPLC conditions, retention times were 4.03min for CIM, 6.99min for MT and 8.49min for PR. The method was validated according to ICH Q2 (R1) guideline for specificity, linearity, sensitivity, precision, accuracy, stability and robustness. Developed method was linear and determination coefficients of the calibration curves were 0.9993, 0.9991 and 1.0 for CIM, MT and PR, respectively. The limits of quantification were 6.20, 2.78 and 0.45μg/mL for CIM, MT and PR, respectively. The precision and accuracy values of the developed analytical method met the ICH Q2 (R1) limits. The applicability of the method was demonstrated by preliminary in-situ intestinal perfusion studies. In conclusion, samples obtained from in-situ intestinal perfusion studies performed to examine the absorption/permeability of CIM, MT, and PR can be analyzed with the developed HPLC method.

HPLC-MS standardization and validation methods for determination of calactin content in dichloromethane fraction of Calotropis gigantea (L.) Dryand. (Niu jiao gua) stem bark and its application in prediction of anticancer activities.

Calactin, a doubly-linked cardenolide, is commonly found in Apocynaceae family including Calotropis gigantea (L.) Dryand. (Niu jiao gua, C. gigantea). This phytochemical has gained recognition for its potential as an anticancer agent and a marker for anticancer properties. Our previous reports demonstrated the remarkable anti-liver and anti-colon cancer activities both in vitro and in vivo of the dichloromethane fraction from the stem barks of C. gigantea (CGD). However, quantitative analysis of calactin content in CGD by using a high-performance liquid chromatography (HPLC) - ultraviolet (UV) method was limited. Therefore, this study aimed to develop more sensitive and reliable method for measurement of calactin in CGD by using a HPLC- electrospray ionization mass spectrometry (ESI-MS) for its application on quality control and prediction of anticancer activity of CGD. The study utilized a HPLC-ESI-MS system, negative mode, for standardization and validation. An octadecylsilane column and a mixture of acetonitrile and water containing 0.1% formic acid in gradient system were used as a stationary phase and a mobile phase, respectively. The method was validated in terms of linearity, accuracy, precision, recovery, limit of detection (LOD), and limit of quantitation (LOQ). The linearity of the developed technique was verified within the calactin concentrations range from 1 to 50μg/mL, exhibiting a linear coefficient of determination (R2) greater than 0.998. The LOD and LOQ were 0.1 and 1μg/mL, respectively. The proposed methodology met the acceptance criteria according to the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH) guideline Q2(R1). Therefore, the method was suitable for the quality control of CGD. Additionally, we suggest applying the established protocol to quantify the calactin contents in CGDs collected over a period of one year (12 months) to investigate the correlation to their cytotoxicities against human cell lines derived from colon cancer (HCT116), human hepatoblastoma (HepG2) and human cell line derived from stomach cancer metastasized to liver (MKN74). This will help in predicting its cytotoxicity against HCT116, HepG2 and MKN74. In summary, the established HPLC-ESI-MS method is suitable for both quality control and predicting of CGD anticancer activities for further utilization.

Simulated radiation shielding parameter for energy 1 keV-100 GeV of lead-free borotellurite based glass for nuclear medicine application

This paper studies on the theoretical ionizing radiation shielding parameter for the glass of {[(TeO2)0.7 (B2O3)0.3]0.7 [ZnO]0.3}1-x {CeO2}x by using two software; WinXCOM and PhyX software, which investigate the ability of cerium oxide. The investigation revealed that the 5CeZBTe glass sample, which included the greatest concentration of CeO2 (0.05 mol), showed the greatest linear attenuation coefficient (LAC) and least values in Half Value Layer (HVL) and Mean Free Path (MFP). These results suggest that 5CeZBTe glass has significant potential as an alternative to traditional lead-based radiation shielding, offering a safer environment for both patients and healthcare professionals in medical settings.

PENGARUH PERSEPSI KEMUDAHAN PENGGUNAAN, PERSEPSI MANFAAT, DAN PERSEPSI KEPERCAYAAN TERHADAP MINAT PENGGUNAAN QRIS SEBAGAI ALAT TRANSAKSI PEMBAYARAN DIGITAL DI KOTA PEKANBARU

The purpose of this study is to determine the influence of perceived ease of use, perceived usefulness, and perceived trust on the intention to use QRIS as a digital transaction tool in Pekanbaru City. This research employs a quantitative approach with a sampling technique based on Hair's formula, involving 160 respondents. Data were collected through the distribution of questionnaires, using both primary and secondary data sources. The study applies descriptive statistical analysis, respondent response analysis, validity testing, reliability testing, normality testing, heteroscedasticity testing, multicollinearity testing, multiple linear regression analysis, t-tests, and determination coefficient analysis, processed using SPSS version 26. The results indicate that the perceived ease of use (X1) and perceived usefulness (X2) variables have a positive and significant influence on the intention to use (Y). Conversely, the perceived trust variable (X3) has a positive but not significant influence on the intention to use (Y).

Development and Characterization of a W8Ni3Cu Alloy for Gamma Radiation Shielding

This study investigates the potential of a W8Ni3Cu alloy as a gamma radiation shielding material for transporting highly radioactive substances. The alloy, composed of tungsten (W), nickel (Ni), and copper (Cu), was characterized using X-ray diffraction after sintering, revealing a body-centered-cubic crystal structure with an α-tungsten phase and a secondary γ-nickel-tungsten (Ni17W3) phase. The gamma radiation attenuation coefficients of the alloy were measured using a 60Co source. The results showed linear attenuation coefficients of 0.688 cm-1 for the alloy sintered at 1200°C and 0.488 cm-1 for the alloy sintered at 1300°C. These values are 34% and 53% lower than the reference value of pure tungsten (1.044 cm-1), but they still demonstrate adequate shielding properties for practical use. The findings suggest that the W8Ni3Cu alloy is a promising candidate for fabricating containers for the safe transport of radioactive material.

PENGARUH RETURN ON ASSET (ROA) CURRENT RATIO (CR) DAN EARNING PER SHARE (EPS) TERHADAP HARGA SAHAM PADA PT MAYORA INDAH TBK PERIODE 2013-2022

ABSTRACT This study aims to determine the effect of Return On Asset (ROA) Current Ratio (CR) and Earning Per Share (EPS) on the share price of PT Mayora Indah Tbk for the period 2013-2022. This research uses Descriptive Quantitative methods with hypothesis testing. This research used descriptive statistical tests, classical assumption tests, multiple linear regression tests, hypothesis tests (t tests and f tests), and coefficient of determination tests with the help of the SPSS (Statistical Product Service Solution) program version 26. Based on the hypothesis test perisal Effect of Return On Asset (X1) show sthat t count &lt; t table where 1.016 &lt; 2.364 and a significant value of 0.349 &gt; 0.05, so that Return On Asset has no effect and is not significant to the stock price.T heresults of hypothesis testing in terms of the effect of Current Ratio (X2) show that tcount &lt; t table where 1,260 &lt; 2,364 and a significant value of 0.255&gt; 0.05, so that Current Ratio has no effect and is not significant to stock prices.The results of hypothesis testing in terms of the effect of Earning Per Share (X3) show that t count &gt; T table where-2.752 &gt; 2.364 and a significant value of 0.03 &lt; 0.05 so that Earning Per Share has a negative and significant effecton Stock Price.The test results simultan eously show that f count &gt; f table where 5.343 &gt; 4,35 with asignificant 0.039 &lt; 0.05. so it can be concluded that Return On Asset, Current Ratio, and Earning Per Share havea significant effect on Price. Keywords: ROA, CR, EPS and stock Price.

ПЛАСТИЧНОСТЬ СОРТОВ ЯРОВОЙ ПШЕНИЦЫ В УСЛОВИЯХ КРАСНОЯРСКОЙ ЛЕСОСТЕПИ

The purpose of the study is to evaluate the ecological plasticity of spring wheat varieties. Objectives: to evaluate the plasticity of spring wheat in terms of stress resistance, yield, ecological plasticity index, linear regression coefficient; to study the criterion of reliability and plasticity of spring wheat varieties. The location of the study is the Uyarsk GSU, located in the forest-steppe zone of the Krasnoyarsk Region. The objects of the study are 21 varieties of spring wheat, including 19 varieties of spring soft wheat of early ripening, mid-early, mid-ripening, mid-late groups and 2 varieties of spring durum wheat. For soft wheat, the Novosibirskaya 15 variety acted as a control in the early-ripening group of varieties, Altaiskaya 70 in the middle-early group, Altaiskaya 75 in the middle-ripening group, Lider 80 in the middle-late group, and the Oazis variety was the control among durum wheat varieties. A tendency to increase the yield from durum to soft varieties was revealed, among soft wheat varieties – from early ripening to mid-late group. In terms of the yield of soft wheat, the best results (more than 7.0 t/ha) were obtained in the varieties Extra (early ripening), Novosibirskaya 41 (medium-early), Gonets, Omskaya 44, Kuraginskaya 2, Predgornaya (mid-ripening), Lider 80, Union (medium-late), in terms of durum wheat productivity – Omskaya steppe. Data processing according to the method proposed by D.A. Saprygin, made it possible to carry out a comprehensive analysis and determine the plasticity of spring wheat varieties. Based on the results of such an analysis, it can be said that the highest reliability criterion (RC) is for soft wheat varieties of the early ripening group Novosibirskaya 15, Novosibirskaya 16; mid-early group Novosibirskaya 31, Novosibirskaya 41, Pamyati Vavenkov, mid-season group Gonets, Omskaya 44, mid-late group Leader 80, Belukha, Junior, as well as in the durum wheat variety Omskaya steppe.

The association between personality traits and transphobia among university students: a cross-sectional study in northwestern Iran

BackgroundIndividuals with GD may suffer from limited access to healthcare services because of negative attitudes from the healthcare providers. Therefore, to promote medical service it is of great importance to address negative attitudes among healthcare providers. The present study aimed to estimate the prevalence of transphobia as well as to assess the association between personality traits and transphobia among students of the University of Medical Sciences, who will hold key positions within the healthcare system.MethodsThis cross-sectional study was conducted on 418 students at Tabriz in northwestern Iran in 2024. Convenience sampling method was utilized. Data were gathered through standard self-reported questioners; Genderism and Transphobia Scale (GTS), and Big Five Inventory scale (BFI-44). Linear regression analysis was conducted to estimate standard coefficient with 95% Confidence Intervals (CIs).ResultsThe response rate was calculated as 98.35% in which 204 (48.8%) out of the participants were female. The mean (SD) age was 23.73 (2.01) years. The adjusted multiple linear regression coefficients indicated that the agreeableness (β = 0.16, p = 0.001), neuroticism (β = 0.11, p = 0.02), and openness (β = -0.27, p = 0.001) were able to effectively explain the variance in transphobia scores. However, conscientiousness (β = 0.06, p = 0.18) and extroversion (β = 0.06, p = 0.05) did not significantly contribute to explaining the variance in transphobia scores.ConclusionsPersonality traits may significantly influence attitudes toward transgender individuals, suggesting that interventions designed to reduce transphobia should consider these foundational personality characteristics.Clinical trial numberNot applicable.

Optimization of Thermal Insulation Parameters for Vertical Perimeters in Buildings with Single-Layer Walls

This article presents the results of a study on the impact of selected parameters of a building’s ground-floor zone (the junction of the external and foundation walls, the ground floor slab, and the ground itself) on the temperature field within the external envelope. This study aims to analyze the influence and optimize the parameters of vertical perimeter insulation in the ground-floor zone of the building. Mathematical modeling was selected as the research method. This paper analyzes the relationships between the temperature ϑimg on the inner surface of the wall at the analyzed node and the linear thermal transmittance coefficient ψim of the thermal bridge occurring in this location, as influenced by the following parameters: dp—thickness of the insulation layer in the ground floor slab; df—thickness of the vertical perimeter insulation layer in the foundation wall; t—location of the insulation layer in the ground floor slab relative to the “external wall-foundation wall” contact surface; r—location of the vertical perimeter insulation layer in the foundation wall; and λs—thermal conductivity of the single-layer external wall material. The analysis was conducted under the climatic conditions of Białystok, Poland. Using THERM 7.6 software for computational experiments, data were obtained to develop deterministic mathematical models of these relationships. The models enabled the assessment of the degree and nature of the influence of the studied factors on ϑimg and ψim, optimization of selected parameters, and mathematical description of safe operating conditions for external walls in the ground-floor zone of heated buildings. It was found that the parameters dp, df, and r have favorable effects, increasing ϑimg by 2.57%, 2.51%, and 4.17%, respectively, when varying from their minimum to maximum levels. Conversely, the parameters t and λs negatively impact ϑimg, contributing reductions of −12.01% and −4.66%, respectively, with a cumulative effect of −16.67%. Optimal parameter values were determined based on energy efficiency criteria. This information may be useful for researchers, designers, engineers, and decision-makers when making informed decisions during the design phase of heated buildings.

Relevance of body weight adaptation and modern obesity-defining parameters in the analysis of isokinetic trunk strength in people with obesity - A retrospective analysis.

Pathologic values of body mass index (BMI), body weight, and waist circumference correlate with higher absolute and lower relative trunk strength. Whether waist-to-height ratio (WHtR) is appropriate for showing trunk strength differences in people with obesity and whether a continuous linear relationship exists between the increase in obesity and trunk strength is unknown. This retrospective cross-sectional study included 1174 subjects (1114 men and 60 women). Measured values included body weight, height, waist circumference, WHtR, BMI, and both absolute and body weight-adapted trunk flexor/extensor strength. Statistical analyses included t-tests, Welch tests, Pearson correlations, mixed-linear, and nonlinear regression analyses. Positive correlations with absolute trunk strength were found in subjects without obesity for all anthropometric parameters except WHtR. Weaker positive and partly negative correlation and linear regression coefficients were found in subjects with obesity. Nonlinear relationships were found between age, BMI, WHtR, and absolute respective body weight-adapted trunk strength. The relationship between obesity-defining measures/ indices and trunk strength is non-linear. Increasing BMI, waist circumference, or WHtR above cut-off values known from cardiovascular research is linked to a decrease or weaker increase in trunk strength. Body weight adaptation is recommended to avoid misinterpretation of apparently good absolute trunk strength values in people with obesity.

Preparation and Characterizations of Intrinsically Black Polyesterimide Films with Good Thermal Endurance at Elevated Temperatures for Potential Two-Layer Flexible Copper Clad Laminate Applications

Polymer films with combined properties of good thermoplasticity, good electrical properties, and good thermal endurance are highly required for two-layer flexible copper clad laminate (FCCL) applications. Meanwhile, the black appearance is also required for specific FCCL applications. Therefore, in the present work, a series of ester-linked polyimide (PEsI) films were designed and developed via the copolymerization chemistry of an ester-containing dianhydride of biphenyl dibenzoate-3,3′,4,4′-tetracarboxylic acid dianhydride (BPTME), a rigid-rod dianhydride of 3,3′,4,4′-biphenyltetracarboxylic acid dianhydride (BPDA), an ester-bridged diamine of 2-(4-aminobenzoate)-5-aminobiphenyl (ABABP), and a functional diamine of 4,4′-iminodianiline (NDA). The molar proportion of the BPTME/BPDA was fixed to be 20:80 and that of ABABP/NDA increased from 50:50 for PEsI-1 to 0:100 for PEsI-VI. The afforded PEsI films showed obviously enhanced blackness with the increasing molar ratio of NDA in the polymers. The PEsI-VI film exhibited the optical transmittance values of 0 and 27.4% at the wavelength of 500 nm (T500) and 760 nm (T760), respectively. The values were apparently lower than those of the standard PI-ref produced from common pyromellitic dianhydride (PMDA) and 4,4′-oxydianiline (ODA) (T500 = 63.2%; T760 = 86.3%). Meanwhile, the PEsI-V film showed good blackness with the CIE Lab optical parameters of 1.83 for L*, 11.46 for a*, 3.13 for b*, and 0 for haze. The PEsI samples exhibited good thermoplasticity and the storage and loss modulus of the films rapidly decreased around the glass transition temperatures (Tg) in the dynamic mechanical analysis (DMA) tests. The PEsI samples revealed the Tg values from 247.2 °C to 286.1 °C in the differential scanning calorimetry (DSC) measurements. The PEsI samples exhibited the linear coefficients of thermal expansion (CTE) of (27.1~33.4) × 10−6/K from 50 to 250 °C, which was comparable to that of the PI-ref sample (CTE = 29.5 × 10−6/K), however, a bit higher than that of the copper foil (CTE = 17.0 × 10−6/K).

The seepage flow state characteristics of SMA-13 asphalt mixture under triaxial fatigue load

Abstract The seepage flow state of water in asphalt pavement may not accordant with Darcy law due to the high hydrodynamic pressure generated under high-speed traffic load, In order to study the seepage flow state of water in asphalt pavement under high water pressure conditions and analyze the critical conditions for non Darcy flow to occur, the SMA-13 asphalt mixture with different compaction methods and different percent air voids were prepared, and triaxial fatigue tests and high water pressure seepage tests were conducted on the specimens, hydraulic gradient and critical Reynolds number were used to distinguish Darcy and non Darcy phenomena in the seepage process. The results indicate that the linear flow occurs at low flow velocity in the SMA-13 asphalt mixture with different compaction methods and different percent air voids, it shows obvious nonlinear flow at high flow velocity. The values of linear component coefficient a and nonlinear component coefficient b obtained by nonlinear fitting by using Forchheimer's law decrease with the increase of percent air voids, and the values of the coefficients of specimens formed by rotary compaction molding are larger than those formed by Marshall compaction molding. The critical flow velocity and critical Reynolds number increase with the increase of percent air voids before and after triaxial fatigue loading with different molding methods.

Experimental study of different oxides in B2O3–ZnO–BaO glass system for gamma-ray shielding

Glass system of 45B2O3–20ZnO–30BaO–5X, (where X represents CaO, MgO, Al2O3, TiO2, CuO and Fe2O3) in mole percentage was investigated for gamma ray radiation shielding experimentally. Six glass composites were fabricated and the density was measured experimentally and the BZBCa glass sample has the least density with a value of 3.932 g cm−3 and this is due to the presence of CaO in it, and the sample BZBFe has the highest density with a value of 4.031 g cm−3. Through comparing the linear attenuation coefficient (LAC) data (experimental and Phy-X) for the BZBX glass samples, the LAC values for glass samples obtained experimentally and using Phy-X are in a very close range. All the glass samples have the greatest LAC values at 0.0595 MeV, the lowest energy value. Sample BZBCu has a LAC value of 16.203 1/cm, which is also the highest LAC value among all the studied glasses, this is as a result of the high density of this glass and due to the high atomic number of Cu. The glasses’ transmission factor (TF) at 1 cm thickness against energy was determined. The TF values of all the glasses were almost zero. The TF values increased significantly for all the glasses when the energy was increased to 0.662 MeV, and for sample BZBCa its TF value increases 74.08%, which was the highest TF value increase. The half-value layer and other shielding parameters have been determined experimentally.